1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * System Control Driver
4 *
5 * Copyright (C) 2012 Freescale Semiconductor, Inc.
6 * Copyright (C) 2012 Linaro Ltd.
7 *
8 * Author: Dong Aisheng <dong.aisheng@linaro.org>
9 */
10
11 #include <linux/clk.h>
12 #include <linux/err.h>
13 #include <linux/hwspinlock.h>
14 #include <linux/io.h>
15 #include <linux/init.h>
16 #include <linux/list.h>
17 #include <linux/of.h>
18 #include <linux/of_address.h>
19 #include <linux/of_platform.h>
20 #include <linux/platform_data/syscon.h>
21 #include <linux/platform_device.h>
22 #include <linux/regmap.h>
23 #include <linux/mfd/syscon.h>
24 #include <linux/slab.h>
25
26 static struct platform_driver syscon_driver;
27
28 static DEFINE_SPINLOCK(syscon_list_slock);
29 static LIST_HEAD(syscon_list);
30
31 struct syscon {
32 struct device_node *np;
33 struct regmap *regmap;
34 struct list_head list;
35 };
36
37 static const struct regmap_config syscon_regmap_config = {
38 .reg_bits = 32,
39 .val_bits = 32,
40 .reg_stride = 4,
41 };
42
of_syscon_register(struct device_node * np,bool check_clk)43 static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
44 {
45 struct clk *clk;
46 struct syscon *syscon;
47 struct regmap *regmap;
48 void __iomem *base;
49 u32 reg_io_width;
50 int ret;
51 struct regmap_config syscon_config = syscon_regmap_config;
52 struct resource res;
53
54 syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
55 if (!syscon)
56 return ERR_PTR(-ENOMEM);
57
58 if (of_address_to_resource(np, 0, &res)) {
59 ret = -ENOMEM;
60 goto err_map;
61 }
62
63 base = of_iomap(np, 0);
64 if (!base) {
65 ret = -ENOMEM;
66 goto err_map;
67 }
68
69 /* Parse the device's DT node for an endianness specification */
70 if (of_property_read_bool(np, "big-endian"))
71 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
72 else if (of_property_read_bool(np, "little-endian"))
73 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
74 else if (of_property_read_bool(np, "native-endian"))
75 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;
76
77 /*
78 * search for reg-io-width property in DT. If it is not provided,
79 * default to 4 bytes. regmap_init_mmio will return an error if values
80 * are invalid so there is no need to check them here.
81 */
82 ret = of_property_read_u32(np, "reg-io-width", ®_io_width);
83 if (ret)
84 reg_io_width = 4;
85
86 ret = of_hwspin_lock_get_id(np, 0);
87 if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {
88 syscon_config.use_hwlock = true;
89 syscon_config.hwlock_id = ret;
90 syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
91 } else if (ret < 0) {
92 switch (ret) {
93 case -ENOENT:
94 /* Ignore missing hwlock, it's optional. */
95 break;
96 default:
97 pr_err("Failed to retrieve valid hwlock: %d\n", ret);
98 fallthrough;
99 case -EPROBE_DEFER:
100 goto err_regmap;
101 }
102 }
103
104 syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%pa", np, &res.start);
105 syscon_config.reg_stride = reg_io_width;
106 syscon_config.val_bits = reg_io_width * 8;
107 syscon_config.max_register = resource_size(&res) - reg_io_width;
108
109 regmap = regmap_init_mmio(NULL, base, &syscon_config);
110 kfree(syscon_config.name);
111 if (IS_ERR(regmap)) {
112 pr_err("regmap init failed\n");
113 ret = PTR_ERR(regmap);
114 goto err_regmap;
115 }
116
117 if (check_clk) {
118 clk = of_clk_get(np, 0);
119 if (IS_ERR(clk)) {
120 ret = PTR_ERR(clk);
121 /* clock is optional */
122 if (ret != -ENOENT)
123 goto err_clk;
124 } else {
125 ret = regmap_mmio_attach_clk(regmap, clk);
126 if (ret)
127 goto err_attach;
128 }
129 }
130
131 syscon->regmap = regmap;
132 syscon->np = np;
133
134 spin_lock(&syscon_list_slock);
135 list_add_tail(&syscon->list, &syscon_list);
136 spin_unlock(&syscon_list_slock);
137
138 return syscon;
139
140 err_attach:
141 if (!IS_ERR(clk))
142 clk_put(clk);
143 err_clk:
144 regmap_exit(regmap);
145 err_regmap:
146 iounmap(base);
147 err_map:
148 kfree(syscon);
149 return ERR_PTR(ret);
150 }
151
device_node_get_regmap(struct device_node * np,bool check_clk)152 static struct regmap *device_node_get_regmap(struct device_node *np,
153 bool check_clk)
154 {
155 struct syscon *entry, *syscon = NULL;
156
157 spin_lock(&syscon_list_slock);
158
159 list_for_each_entry(entry, &syscon_list, list)
160 if (entry->np == np) {
161 syscon = entry;
162 break;
163 }
164
165 spin_unlock(&syscon_list_slock);
166
167 if (!syscon)
168 syscon = of_syscon_register(np, check_clk);
169
170 if (IS_ERR(syscon))
171 return ERR_CAST(syscon);
172
173 return syscon->regmap;
174 }
175
device_node_to_regmap(struct device_node * np)176 struct regmap *device_node_to_regmap(struct device_node *np)
177 {
178 return device_node_get_regmap(np, false);
179 }
180 EXPORT_SYMBOL_GPL(device_node_to_regmap);
181
syscon_node_to_regmap(struct device_node * np)182 struct regmap *syscon_node_to_regmap(struct device_node *np)
183 {
184 if (!of_device_is_compatible(np, "syscon"))
185 return ERR_PTR(-EINVAL);
186
187 return device_node_get_regmap(np, true);
188 }
189 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
190
syscon_regmap_lookup_by_compatible(const char * s)191 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
192 {
193 struct device_node *syscon_np;
194 struct regmap *regmap;
195
196 syscon_np = of_find_compatible_node(NULL, NULL, s);
197 if (!syscon_np)
198 return ERR_PTR(-ENODEV);
199
200 regmap = syscon_node_to_regmap(syscon_np);
201 of_node_put(syscon_np);
202
203 return regmap;
204 }
205 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
206
syscon_regmap_lookup_by_phandle(struct device_node * np,const char * property)207 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
208 const char *property)
209 {
210 struct device_node *syscon_np;
211 struct regmap *regmap;
212
213 if (property)
214 syscon_np = of_parse_phandle(np, property, 0);
215 else
216 syscon_np = np;
217
218 if (!syscon_np)
219 return ERR_PTR(-ENODEV);
220
221 regmap = syscon_node_to_regmap(syscon_np);
222 of_node_put(syscon_np);
223
224 return regmap;
225 }
226 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
227
syscon_regmap_lookup_by_phandle_args(struct device_node * np,const char * property,int arg_count,unsigned int * out_args)228 struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np,
229 const char *property,
230 int arg_count,
231 unsigned int *out_args)
232 {
233 struct device_node *syscon_np;
234 struct of_phandle_args args;
235 struct regmap *regmap;
236 unsigned int index;
237 int rc;
238
239 rc = of_parse_phandle_with_fixed_args(np, property, arg_count,
240 0, &args);
241 if (rc)
242 return ERR_PTR(rc);
243
244 syscon_np = args.np;
245 if (!syscon_np)
246 return ERR_PTR(-ENODEV);
247
248 regmap = syscon_node_to_regmap(syscon_np);
249 for (index = 0; index < arg_count; index++)
250 out_args[index] = args.args[index];
251 of_node_put(syscon_np);
252
253 return regmap;
254 }
255 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args);
256
257 /*
258 * It behaves the same as syscon_regmap_lookup_by_phandle() except where
259 * there is no regmap phandle. In this case, instead of returning -ENODEV,
260 * the function returns NULL.
261 */
syscon_regmap_lookup_by_phandle_optional(struct device_node * np,const char * property)262 struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np,
263 const char *property)
264 {
265 struct regmap *regmap;
266
267 regmap = syscon_regmap_lookup_by_phandle(np, property);
268 if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV)
269 return NULL;
270
271 return regmap;
272 }
273 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional);
274
syscon_probe(struct platform_device * pdev)275 static int syscon_probe(struct platform_device *pdev)
276 {
277 struct device *dev = &pdev->dev;
278 struct syscon_platform_data *pdata = dev_get_platdata(dev);
279 struct syscon *syscon;
280 struct regmap_config syscon_config = syscon_regmap_config;
281 struct resource *res;
282 void __iomem *base;
283
284 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
285 if (!syscon)
286 return -ENOMEM;
287
288 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
289 if (!res)
290 return -ENOENT;
291
292 base = devm_ioremap(dev, res->start, resource_size(res));
293 if (!base)
294 return -ENOMEM;
295
296 syscon_config.max_register = resource_size(res) - 4;
297 if (pdata)
298 syscon_config.name = pdata->label;
299 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
300 if (IS_ERR(syscon->regmap)) {
301 dev_err(dev, "regmap init failed\n");
302 return PTR_ERR(syscon->regmap);
303 }
304
305 platform_set_drvdata(pdev, syscon);
306
307 dev_dbg(dev, "regmap %pR registered\n", res);
308
309 return 0;
310 }
311
312 static const struct platform_device_id syscon_ids[] = {
313 { "syscon", },
314 { }
315 };
316
317 static struct platform_driver syscon_driver = {
318 .driver = {
319 .name = "syscon",
320 },
321 .probe = syscon_probe,
322 .id_table = syscon_ids,
323 };
324
syscon_init(void)325 static int __init syscon_init(void)
326 {
327 return platform_driver_register(&syscon_driver);
328 }
329 postcore_initcall(syscon_init);
330
